Revert "move dot_column_engraver to Voice"

This reverts commit 41b248ddea66f8803815aded606ed7300778b0eb.
And adds a regression test.

1 files changed, 22 insertions, 0 deletions

diff --git a/input/regression/dot-column-engraver.ly b/input/regression/dot-column-engraver.ly
new file mode 100644
index 0000000000..8ea30b91e5
--- /dev/null
+++ b/input/regression/dot-column-engraver.ly
@@ -0,0 +1,22 @@
+\version "2.15.34"
+
+\header {
+  texidoc = "Dot Columns are engraved in the Staff by default,
+enabling dots to move vertically to make room for dots from another voice.
+If Dot_column_engraver is moved to Voice, separate dot columns are engraved,
+and these dots avoid notes in other voices."
+}
+
+music = \relative c'' { \time 3/4 << {
+  <d f g>4. c c b g f a <a b> a <a' b>
+} \\ \times 1/2 {
+  <f, g b>2. a-- <a b> <g a>-. a2. a-- a a b <a b> \bar "|."
+} >> }
+
+\score{ \music }
+\markup "move Dot_column_engraver to Voice :"
+\score{ \music
+\layout {
+  \context {\Staff \remove Dot_column_engraver}
+  \context {\Voice \consists Dot_column_engraver}
+}}